© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 1 Version 4.0 Communicating over the Network Network Fundamentals – Chapter 2

2 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Objectives  Describe the structure of a network, including the devices and media that are necessary for successful communications.  Explain the function of protocols in network communications.  Explain the advantages of using a layered model to describe network functionality.  Describe the role of each layer in two recognized network models: The TCP/IP model and the OSI model.  Describe the importance of addressing and naming schemes in network communications.

3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Structure  Define the elements of communication –3 common elements of communication Message source The channel Message destination  Define a network –Data or information networks capable of carrying many different types of communications

4 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Structure  Describe how messages are communicated –Data is sent across a network in small “chunks” called segments

5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Structure  Define the components of a network –Network components Hardware Software

6 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Structure  End Devices and their Role in the Network –End devices form interface with human network & communications network –Role of end devices: Client Server Both client and server

7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Structure  Identify the role of an intermediary device in a data network and be able to contrast that role with the role of an end device –Role of an intermediary device Provides connectivity and ensures data flows across network

8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Structure  Define network media and criteria for making a network media choice –Network media – this is the channel over which a message travels

9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Types  Define Local Area Networks (LANs) –A network serving a home, building or campus is considered a Local Area Network (LAN)

10 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Types  Define Wide Area Networks (WANs) –LANs separated by geographic distance are connected by a network known as a Wide Area Network (WAN)

11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Types  Define the Internet –The internet is defined as a global mesh of interconnected networks

12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Types  Describe network representations

13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Function of Protocol in Network Communication  The importance of protocols and how they are used to facilitate communication over data networks –A protocol is a set of predetermined rules

14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Function of Protocol in Network Communication  Explain network protocols –Network protocols are used to allow devices to communicate successfully

15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Function of Protocol in Network Communication  Describe Protocol suites and industry standards –A standard is a process or protocol that has been endorsed by the networking industry and ratified by a standards organization

16 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Function of Protocol in Network Communication  Define different protocols and how they interact

17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Function of Protocol in Network Communication  Technology independent Protocols –Many diverse types of devices can communicate using the same sets of protocols –This is because protocols specify network functionality, not the underlying technology to support this functionality

18 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Layers with TCP/IP and OSI Model  Explain the benefits of using a layered model –Benefits include Assists in protocol design Fosters competition Changes in one layer do not affect other layers Provides a common language

19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Layers with TCP/IP and OSI Model  Describe TCP/IP Mode

20 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Layers with TCP/IP and OSI Model  Describe the Communication Process

21 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Layers with TCP/IP and OSI Model  Explain protocol data units (PDU) and encapsulation

22 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Layers with TCP/IP and OSI Model  Describe the process of sending and receiving messages

23 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Layers with TCP/IP and OSI Model  Explain protocol and reference models –A protocol model provides a model that closely matches the structure of a particular protocol suite –A reference model provides a common reference for maintaining consistency within all types of network protocols and services

24 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Layers with TCP/IP and OSI Model  Define OSI

25 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Layers with TCP/IP and OSI Model  Compare OSI and TCP/IP model

26 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 26 The OSI Reference Model  The OSI reference model is the primary model for network communications.  Allows you to view the network functions that occur at each layer.  It is a framework that you can use to understand how information travels throughout a network  7 layers -- each of which illustrates a particular network function.

27 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 27 OSI – The Application Layer  Provides network services to the user's applications.  It does not provide services to any other OSI layer  ***Think of any network application you use daily

28 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 28 OSI – The Presentation Layer  It ensures that the information that the application layer of one system sends out is readable by the application layer of another system.  *** Think of any common file formats (JPEG, txt etc)

29 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 29 OSI – The Session Layer  *** After you prepare your data, you need to establish the communication channels to send data  This layer establishes, manages, and terminates sessions between two communicating hosts.  It also synchronizes dialogue between the two hosts' presentation layers and manages their data exchange.

30 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 30 OSI – The Transport Layer  Data will be segmented and send to destination device. Transport layer of destination device will reassemble them.  This layer handles details of reliable transfer. (ensures that the data arrive completely )

31 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 31 OSI – The Network Layer  Many paths to the same destination. So, which path to follow?  Segmented data needs address to reach the destination (network address)  This layer handle 2 above stated issues.

32 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 32 OSI – The Data Link Layer  It provides means for exchanging data frames over a common media  To detect and possibly correct errors that may occur in the Physical layer  Physical Addressing, topologies and flow control

33 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 33 OSI – The Physical Layer  It defines the electrical, mechanical, procedural, and functional specifications for activating, maintaining, and deactivating the physical link between end systems.  Voltage levels, timing of voltage changes, physical data rates, maximum transmission distances, physical connectors, and other, similar, attributes defined by physical layer specifications.

34 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 34 TCP/IP Model Network Access: Detailing the components that make up the psysical link and how to access it

35 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 35 Comparison --Both have application layers, though they include very different services --Both have comparable transport and network (Internet) layers --TCP/IP combines the presentation and session layer issues into its application layer --TCP/IP combines the OSI data link and physical layers into one layer --TCP/IP appears simpler because it has fewer layers

36 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 36 Data Encapsulation  Build the data  Package the data for end to end support (Segments)  The data is put into a packet or datagram that contains a network header with source and destination logical addresses PDU: Transport layer: Segment, Network: Packet, Data Link: Frame

37 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Data Encapsulation  Each network device must put the packet into a frame.  The frame must be converted into a pattern of 1s and 0s (bits)  ***Data  Segments  Packet  Frames  Bits 37 Network header: IP address (host), Frame header: MAC address (physical address)

38 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 38 Addressing in the Network  There are various types of addresses that must be included to successfully deliver the data from a source application running on one host to the correct destination application running on another Transport Layer (#4): to identify the processes or services that are communicating within the end devices

39 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Addressing and Naming Schemes  Explain how labels in encapsulation headers are used to manage communication in data networks

40 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Addressing and Naming Schemes  Describe examples of Ethernet MAC Addresses, IP Addresses, and TCP/UDP Port numbers

41 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Addressing and Naming Schemes  Explain how labels in encapsulation headers are used to manage communication in data networks

42 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Addressing and Naming Schemes  Describe how information in the encapsulation header is used to identify the source and destination processes for data communication

43 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Summary

44 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public